diff options
| -rw-r--r-- | kernel/trace/trace_functions_graph.c | 165 |
1 files changed, 131 insertions, 34 deletions
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 45e6c01..a43d009 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -14,9 +14,20 @@ #include "trace.h" #include "trace_output.h" -struct fgraph_data { +struct fgraph_cpu_data { pid_t last_pid; int depth; + int ignore; +}; + +struct fgraph_data { + struct fgraph_cpu_data *cpu_data; + + /* Place to preserve last processed entry. */ + struct ftrace_graph_ent_entry ent; + struct ftrace_graph_ret_entry ret; + int failed; + int cpu; }; #define TRACE_GRAPH_INDENT 2 @@ -384,7 +395,7 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data) if (!data) return TRACE_TYPE_HANDLED; - last_pid = &(per_cpu_ptr(data, cpu)->last_pid); + last_pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); if (*last_pid == pid) return TRACE_TYPE_HANDLED; @@ -435,26 +446,49 @@ static struct ftrace_graph_ret_entry * get_return_for_leaf(struct trace_iterator *iter, struct ftrace_graph_ent_entry *curr) { - struct ring_buffer_iter *ring_iter; + struct fgraph_data *data = iter->private; + struct ring_buffer_iter *ring_iter = NULL; struct ring_buffer_event *event; struct ftrace_graph_ret_entry *next; - ring_iter = iter->buffer_iter[iter->cpu]; + /* + * If the previous output failed to write to the seq buffer, + * then we just reuse the data from before. + */ + if (data && data->failed) { + curr = &data->ent; + next = &data->ret; + } else { - /* First peek to compare current entry and the next one */ - if (ring_iter) - event = ring_buffer_iter_peek(ring_iter, NULL); - else { - /* We need to consume the current entry to see the next one */ - ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL); - event = ring_buffer_peek(iter->tr->buffer, iter->cpu, - NULL); - } + ring_iter = iter->buffer_iter[iter->cpu]; + + /* First peek to compare current entry and the next one */ + if (ring_iter) + event = ring_buffer_iter_peek(ring_iter, NULL); + else { + /* + * We need to consume the current entry to see + * the next one. + */ + ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL); + event = ring_buffer_peek(iter->tr->buffer, iter->cpu, + NULL); + } - if (!event) - return NULL; + if (!event) + return NULL; + + next = ring_buffer_event_data(event); - next = ring_buffer_event_data(event); + if (data) { + /* + * Save current and next entries for later reference + * if the output fails. + */ + data->ent = *curr; + data->ret = *next; + } + } if (next->ent.type != TRACE_GRAPH_RET) return NULL; @@ -640,7 +674,7 @@ print_graph_entry_leaf(struct trace_iterator *iter, if (data) { int cpu = iter->cpu; - int *depth = &(per_cpu_ptr(data, cpu)->depth); + int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); /* * Comments display at + 1 to depth. Since @@ -688,7 +722,7 @@ print_graph_entry_nested(struct trace_iterator *iter, if (data) { int cpu = iter->cpu; - int *depth = &(per_cpu_ptr(data, cpu)->depth); + int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); *depth = call->depth; } @@ -782,19 +816,34 @@ static enum print_line_t print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s, struct trace_iterator *iter) { - int cpu = iter->cpu; + struct fgraph_data *data = iter->private; struct ftrace_graph_ent *call = &field->graph_ent; struct ftrace_graph_ret_entry *leaf_ret; + static enum print_line_t ret; + int cpu = iter->cpu; if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func)) return TRACE_TYPE_PARTIAL_LINE; leaf_ret = get_return_for_leaf(iter, field); if (leaf_ret) - return print_graph_entry_leaf(iter, field, leaf_ret, s); + ret = print_graph_entry_leaf(iter, field, leaf_ret, s); else - return print_graph_entry_nested(iter, field, s, cpu); + ret = print_graph_entry_nested(iter, field, s, cpu); + if (data) { + /* + * If we failed to write our output, then we need to make + * note of it. Because we already consumed our entry. + */ + if (s->full) { + data->failed = 1; + data->cpu = cpu; + } else + data->failed = 0; + } + + return ret; } static enum print_line_t @@ -810,7 +859,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, if (data) { int cpu = iter->cpu; - int *depth = &(per_cpu_ptr(data, cpu)->depth); + int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); /* * Comments display at + 1 to depth. This is the @@ -873,7 +922,7 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent, int i; if (data) - depth = per_cpu_ptr(data, iter->cpu)->depth; + depth = per_cpu_ptr(data->cpu_data, iter->cpu)->depth; if (print_graph_prologue(iter, s, 0, 0)) return TRACE_TYPE_PARTIAL_LINE; @@ -941,8 +990,33 @@ print_graph_comment(struct trace_seq *s, struct trace_entry *ent, enum print_line_t print_graph_function(struct trace_iterator *iter) { + struct ftrace_graph_ent_entry *field; + struct fgraph_data *data = iter->private; struct trace_entry *entry = iter->ent; struct trace_seq *s = &iter->seq; + int cpu = iter->cpu; + int ret; + + if (data && per_cpu_ptr(data->cpu_data, cpu)->ignore) { + per_cpu_ptr(data->cpu_data, cpu)->ignore = 0; + return TRACE_TYPE_HANDLED; + } + + /* + * If the last output failed, there's a possibility we need + * to print out the missing entry which would never go out. + */ + if (data && data->failed) { + field = &data->ent; + iter->cpu = data->cpu; + ret = print_graph_entry(field, s, iter); + if (ret == TRACE_TYPE_HANDLED && iter->cpu != cpu) { + per_cpu_ptr(data->cpu_data, iter->cpu)->ignore = 1; + ret = TRACE_TYPE_NO_CONSUME; + } + iter->cpu = cpu; + return ret; + } switch (entry->type) { case TRACE_GRAPH_ENT: { @@ -952,7 +1026,7 @@ print_graph_function(struct trace_iterator *iter) * sizeof(struct ftrace_graph_ent_entry) is very small, * it can be safely saved at the stack. */ - struct ftrace_graph_ent_entry *field, saved; + struct ftrace_graph_ent_entry saved; trace_assign_type(field, entry); saved = *field; return print_graph_entry(&saved, s, iter); @@ -1030,31 +1104,54 @@ static void print_graph_headers(struct seq_file *s) static void graph_trace_open(struct trace_iterator *iter) { /* pid and depth on the last trace processed */ - struct fgraph_data *data = alloc_percpu(struct fgraph_data); + struct fgraph_data *data; int cpu; + iter->private = NULL; + + data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) - pr_warning("function graph tracer: not enough memory\n"); - else - for_each_possible_cpu(cpu) { - pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid); - int *depth = &(per_cpu_ptr(data, cpu)->depth); - *pid = -1; - *depth = 0; - } + goto out_err; + + data->cpu_data = alloc_percpu(struct fgraph_cpu_data); + if (!data->cpu_data) + goto out_err_free; + + for_each_possible_cpu(cpu) { + pid_t *pid = &(per_cpu_ptr(data->cpu_data, cpu)->last_pid); + int *depth = &(per_cpu_ptr(data->cpu_data, cpu)->depth); + int *ignore = &(per_cpu_ptr(data->cpu_data, cpu)->ignore); + *pid = -1; + *depth = 0; + *ignore = 0; + } iter->private = data; + + return; + + out_err_free: + kfree(data); + out_err: + pr_warning("function graph tracer: not enough memory\n"); } static void graph_trace_close(struct trace_iterator *iter) { - free_percpu(iter->private); + struct fgraph_data *data = iter->private; + + if (data) { + free_percpu(data->cpu_data); + kfree(data); + } } static struct tracer graph_trace __read_mostly = { .name = "function_graph", .open = graph_trace_open, + .pipe_open = graph_trace_open, .close = graph_trace_close, + .pipe_close = graph_trace_close, .wait_pipe = poll_wait_pipe, .init = graph_trace_init, .reset = graph_trace_reset, |
